The present invention relates to communications in computer networks. More specifically, it relates to a method and system for virtual network administration in a data-over-cable system.
Cable television networks such as those provided by Comcast Cable Communications, Inc., of Philadelphia, Pa., Cox Communications of Atlanta, Ga., Tele-Communications, Inc., of Englewood Colo., Time-Warner Cable, of Marietta Ga., Continental Cablevision, Inc., of Boston Mass., and others provide cable television services to a large number of subscribers over a large geographical area. The cable television networks typically are interconnected by cables such as coaxial cables or a Hybrid Fiber/Coaxial (xe2x80x9cHFCxe2x80x9d) cable system which have data rates of about 10 Mega-bits-per-second (xe2x80x9cMbpsxe2x80x9d) to about 30+ Mbps.
The Internet, a world-wide-network of interconnected computers, provides multi-media content including audio, video, graphics and text that typically requires a large bandwidth for downloading and viewing. Most Internet Service Providers (xe2x80x9cISPsxe2x80x9d) allow customers to connect to the Internet via a serial telephone line from a Public Switched Telephone Network (xe2x80x9cPSTNxe2x80x9d) at data rates including 14,400 bps, 28,800 bps, 33,600 bps, 56,000 bps and others that are much slower than the about 10 Mbps to about 30+ Mbps available on a coaxial cable or HFC cable system on a cable television network.
With the explosive growth of the Internet, many customers have desired to use the larger bandwidth of a cable television network to connect to the Internet and other computer networks.
Cable modems, such as those provided by 3Com Corporation, of Santa Clara, Calif., Motorola Corporation, of Arlington Heights, Ill., Hewlett-Packard Co., of Palo Alto, Calif., Bay Networks, of Santa Clara, Calif., Scientific-Atlanta, of Norcross, Ga. and others offer customers higher-speed connectivity to the Internet, an intranet, Local Area Networks (xe2x80x9cLANsxe2x80x9d) and other computer networks via cable television networks. These cable modems currently support a data connection to the Internet and other computer networks via a cable television network with a data rate of up to about 30+ Mbps, which is a much larger data rate than can be supported by a modem used over a serial telephone line.
However, many cable television networks provide only uni-directional cable systems, supporting only a xe2x80x9cdownstreamxe2x80x9d cable data path. A downstream data path is the flow of data from a cable system xe2x80x9cheadendxe2x80x9d to a customer. A cable system headend is a central location in the cable television network that is responsible for sending cable signals in the downstream direction. A return data path via a telephone network (i.e., a xe2x80x9ctelephony returnxe2x80x9d), such as a public switched telephone network provided by ATandT, GTE, Sprint, MCI and others, is typically used for an xe2x80x9cupstreamxe2x80x9d data path. An upstream data path is the flow of data from the customer back to the cable system headend. A cable television system with an upstream connection to a telephony network is called a xe2x80x9cdata-over-cable system with telephony return.xe2x80x9d
An exemplary data-over-cable system with telephony return includes customer premise equipment (e.g., a customer computer), a cable modem, a cable modem termination system, a cable television network, a public switched telephone network, a telephony remote access concentrator and a data network (e.g., the Internet). The cable modem termination system and the telephony remote access concentrator together are called a xe2x80x9ctelephony return termination system.xe2x80x9d
The cable modem termination system receives data packets from the data network and transmits them downstream via the cable television network to a cable modem attached to the customer premise equipment. The customer premise equipment sends response data packets to the cable modem, which sends response data packets upstream via public switched telephone network to the telephony remote access concentrator, which sends the response data packets back to the appropriate host on the data network.
In a two-way cable system without telephony return, the customer premise equipment sends response data packets to the cable modem, which sends the data packets upstream via the cable television network to the cable modem termination system. The cable modem termination system sends the data packets to appropriate hosts on the data network. The cable modem termination system sends the response data packets back to the appropriate cable modem.
As a cable modem is initialized in a data-over-cable system, it registers with a cable modem termination system to allow the cable modem to receive data over a cable television connection and from a data network (e.g., the Internet or an Intranet). The cable modem forwards configuration information it receives in a configuration file during initialization to the cable modem termination system as part of a registration request message. A cable modem also helps initialize and register any attached customer premise equipment with the cable modem termination system.
A cable modem termination system in a data-over-cable system typically manages connections to tens of thousands of cable modems. Most of the cable modems are attached to host customer premise equipment such as a customer computer. To send and receive data to and from a computer network like the Internet or an intranet, a cable modem and customer premise equipment and other network devices have a network address dynamically assigned on the data-over-cable system. Many data-over-cable systems use a Dynamic Host Configuration Protocol (xe2x80x9cDHCPxe2x80x9d) as a standard messaging protocol to dynamically allocate network addresses such as Internet Protocol (xe2x80x9cIPxe2x80x9d) addresses. As is known in the art, the Dynamic Host Configuration Protocol is a protocol for passing configuration information to network devices on a network. The Internet Protocol is an addressing protocol designed to route traffic within a network or between networks.
A cable modem termination system typically handles requests for services on the data-over-cable system cable modems and customer premise equipment. As is known in the art, the Multimedia Cable Network System (xe2x80x9cMCNSxe2x80x9d) Data Over Cable Service Interface Specification system (xe2x80x9cDOCSISxe2x80x9d) is typically used on data-over-cable systems to define server interfaces that provide data services. Other interfaces for other services such as Asymmetric Digital Subscriber Lines (xe2x80x9cADSLxe2x80x9d), Asynchronous Transfer Mode (xe2x80x9cATMxe2x80x9d), Frame Relay, Integrated Services Digital Network (xe2x80x9cISDNxe2x80x9d), Synchronous Optical Networks (xe2x80x9cSONETxe2x80x9d) Voice over Internet Protocol (xe2x80x9cVoIPxe2x80x9d), etc. often require the setting of Quality-of-Service (xe2x80x9cQoSxe2x80x9d), Class-of-Service (xe2x80x9cCoSxe2x80x9d), Type-of-Service (xe2x80x9cToSxe2x80x9d), Service-Level-Agreements (xe2x80x9cSLAxe2x80x9d), and other parameters.
As is known in the art, Class-of-Service is typically defined to provide a reliable (e.g., error free, in sequence, with no loss of duplication) transport facility independent of the quality-of-service. Class-of-service parameters include maximum downstream data rates, maximum upstream data rates, upstream channel priority, guaranteed minimum data rates, guaranteed maximum data rate and other parameters. Quality-of-Service typically collectively specifies the performance of a network service that a device expects on a network. Quality-of-Service parameters include transit delay expected to deliver data to a specific destination, the level of security protection from unauthorized monitoring or modification of data, cost for delivery of data, expected residual error probability, the relative priority associated with the data and other parameters. Type-of-Service typically specifies network tradeoffs that can be made to deliver data. Type-of-Service parameters include minimize delay, maximize throughput, maximize reliability, minimize monetary cost and other parameters. A Service Level Agreement is typically an agreement between a user and a service provider, defining a nature for a provided service and establishing a set of metrics to be used to measure a level of service provided against an agreed upon level of service.
A network device, such as a cable modem termination system, typically provides provisioning services, such as bandwidth provisioning, to allow data services and other services to be used over a data-over-cable system. The provisioning services may be used to provide support for a Virtual Private Network (xe2x80x9cVPNxe2x80x9d) or a Virtual Local Area Network (xe2x80x9cVLANxe2x80x9d). As is known in the art, a virtual private network or a virtual local area network allows networking equipment that may be physically located in several different places to be used to provide a virtual network to a group of users (e.g., at a corporation, university, organization, etc.). The provisioning service may also be used to provide a desired service class (e.g., Class-of-Service, Quality-of-Service, Type-of-Service, Service Level Agreements, etc.) through a data-over-cable system.
There are several problems associated with using a data-over-cable system to provide support for a virtual private network or a virtual local area network. As was described above, many data-over-cable systems use a Dynamic Host Configuration Protocol to dynamically allocate network addresses such as Internet Protocol addresses. However, it is often desirable not to interfere with a network address, such as an Internet Protocol address, assigned to a network device, such as a cable modem, by a network external to the data-over-cable system (e.g., a Local Area Network (xe2x80x9cLANxe2x80x9d)). Such network addresses are often used to provide virtual networking services. However, is difficult with existing data-over-cable systems to allow use of network addresses that are not assigned by the data-over-cable system. This prevents many data-over-cable systems from providing selected virtual networking services.
Another problem is that it is often desirable to allow a first network device, such as a cable modem, connected to a first external network and a data-over-cable system, to request a desired service class (e.g., Class-of-Service, Quality-of-Service, Type-of-Service, Service Level Agreements, etc.) for a desired end-to-end networking service through the data-over-cable system to a second network device on a second external network. However, many existing data-over-cable systems do not have the ability to provide a desired service class for a desired end-to-end networking service through the data-over-cable systems. This prevents many data-over-cable systems from providing selected services classes for desired end-to-end networking services though the data-over-cable systems. Thus, it is desirable to allow a data-over-cable system to be used to provide virtual networking services and services classes for desired end-to-end networking services.
In accordance with preferred embodiments of the present invention, some of the problems associated with providing virtual network services and services classes for desired end-to-end networking services in a data-over-cable system are overcome. A method and system for virtual network administration is provided. One aspect of preferred embodiments of the present invention includes a method for virtual network administration in a data-over-cable system. The method includes receiving a plurality of first messages on a second network device on a data-over-cable system from a plurality of first network devices. The selected first messages from selected first network devices include a virtual networking tag and a network address. The virtual networking tag is used to request a desired networking service on a virtual network. The network address is assigned to a first network device by a network other than the data-over-cable system. It is determined whether a first message includes a virtual networking tag and a network address, and if so, the network address and the virtual networking tag are stored in virtual networking table associated with the second network device. One or more of the network addresses are grouped into a virtual network indicated by a virtual networking tag. The virtual networking tag allows the second network device to provide selected first network devices a desired networking service on the virtual network via the data-over-cable system.
Another aspect of preferred embodiments of the present invention includes a method for virtual network service administration. The method includes receiving a message with a virtual networking tag on a second network device on a data-over-cable system from a first network device connected to the data-over-cable system and a first external network. The virtual networking tag indicates a desired service class for desired end-to-end networking service between the first network device and a third network device on second external network. The desired service class for the desired end-to-end networking service class is mapped into a data-over-cable service class. The data-over-cable service class is mapped into a transport service class for a transport service used on a transport network to provide the desired service class end-to-end for the desired networking service between the first network device and the third network device on the second external network through the data-over-cable system and through the transport network.
In another preferred embodiment of the present invention, a desired service class for a desired end-to-end networking service class indicated by a virtual networking tag is mapped directly into a transport service class by the second network device. In such an embodiment, the step of mapping the desired service class into a data-over-cable service class is not completed.
Preferred embodiments of the present invention may allow first network devices, such as cable modems, to send messages to second network devices, such as cable modem termination systems, including a virtual networking tag. If the messages include a virtual network tag and a network address, the second network device can create a virtual network via a data-over-cable system. The virtual networking tag is also used to request a desired service class for a desired end-to-end networking service. The desired end-to-end networking service is provided through a over-cable system a through the transport network using one or more service class mappings. Thus, preferred embodiments of the present invention may provide a variety of service offerings via and through a data-over-cable system.